Ti₃C₂T_<i>x</i> Aerogel-Based Wearable Humidity Sensors with Low Hysteresis and High Linearity for Expiratory Comfort Management

Wearable and flexible humidity sensors hold great promise for expiratory comfort management. However, the high hysteresis and poor detection linearity restrict the immediate and accurate detection of humidity. Herein, we have prepared Ti₃C₂T_<i>x</i> MXene/chitosan/polyvinylidene difluoride aerogels with a controllable hydrophobic/hydrophilic surface to regulate the catch/escape behavior of H₂O molecules. The MXene aerogel-based humidity sensor demonstrates low hysteresis (3.2% relative humidity) and a high linear relationship (<i>R</i>² = 0.99). Integrated with a control circuit, an expiratory humidity monitoring system is constructed for nasal comfort management as a humidity switch. The exhaled breath humidity can be automatically regulated during dry exhalation conditions. This wearable humidity sensor enables the real-time monitoring and intelligent control of nasal exhaled humidity. This work represents a new avenue for improving breathing comfort and preventing respiratory diseases.